Hydro-ecoregions: a functional approach to the typology of rivers for the European Water Framework Directive

Abstract

The implementation of the EU Water Framework Directive requires a previous typology of aquatic ecosystems based on geographical features. The proposed « Hydro-ecoregion » (HER) approach relies upon the ecosystem hierarchical control concept. Primary determinants of aquatic ecosystems functioning are geology, relief and climate. The cartography of these factors enables the delimitation of 22 first level HER in France. This regionalisation coupled with an ordination of the hydrographic network gives the template for the running waters typology. The concepts, methodology and the HER map are presented.